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AS Heritage 16 HP

This summer, I had a AS Heritage 16 HP (#4A6H6048E1000AA) and AS variable speed air handler (#4TEE3F66A1000AA) installed to replace a GSDX system that had failed beyond reasonable repair. This unit conditions the second floor of my Kansas home. A 3.5ton US Power GSDX continues to condition the main floor and is my benchmark as I've had no trouble with its operation, ecomony or comfort year-round.

The new AS HP cooled our home perfectly all summer but I noticed the fan speed was much faster and never slowed until the last minute or so of the cycle. Now that we are in heating season, I notice the same fan performance but notice that the unit is calling for the electric resistance heat as it recovers from an overnight drop of 4 degrees. Also the air is never warm at the registers like the old GSDX was. Out outdoor temps have been mild, only one night into the teens, the rest in the 20s overnight.

I suspected that the compressor is running in only one stage, even though I understand this is a two stage unit. I checked the thermostat (White-Rogers 1F94-371) and notice there is no wire connected to the Y2 terminal. I stopped my investigation there and called my installer (trusted guy who did all my previous GSDX work). He's due to stop by soon.

Before he arrives, I wanted to get some education on what I should be expecting out of my new system. I learned a lot about my old GSDX and was able to converse with my installer much better that way. I want to have an idea of how this new system should work before he arrives. I've read the installer guides so I know the is specific wiring requirements from the Tstat and also that the fan speeds can be programmed on the control board in the air handler. I suspect the "assistant" installer who did the final day's check out of my new system skipped a step somewhere.

Would appreciate any "education" you guys would consider appropriate! (Promise not to hit my installer in the chops with it when he arrives!)

You haven't violated any rules, but your installer has miss wired your unit. Make sure he sets the air handler blower speeds up correctly based on your outdoor unit and strip heat. In other words read the installation instructions.

X3... I see it all the time. Even the best tech in the world can make a mistake like that. It should be a simple fix for installer.

That is why we started to get all our installers to go through a checklist once install is complete to ensure that every part of the system is working properly. Post back and let us know what your installer said the problem was although it sounds like we already know.

A big part of the problem is most shops start their new guys out as installers. As they get good at installs they get promoted to service technicians. "Advanced systems" (anything other than 1 stage gas, heat pump or electric heat) make up less than 10% of installed systems. Installers who haven't seen an "advanced system" before are more likely to get it wrong.

In some cases they may be rushed/overloaded, therefore not taking the time to read the install instructions. If it works after they hook it up they call it a day. How many installs have you seen where everything is on the default settings the way it comes from the factory? Almost all installs I run into are still on their default settings. Doing things like airflow and static pressure measurements rarely happens in the real world. Sizing for replacement systems is based on the size of what's currently installed plus the amount the customer wants to upsize thinking it will solve comfort issues.

Yes there are those of us interested into the science behind HVAC and are focused on getting it right. Unfortunately most of the work ends up going to the lower bidders who could care less. And guess who gets to go back and fix all the low bidders work....

Obviously you found the problem. Wonder if there are more? But low is 78% of high (at 47 out) so don't expect a big jump in capacity when you do get your high stage hooked up. In the teens & 20s out, don't expect a 4° warmup without using backup even with high. Most of the time the "balance point" is in the mid to upper 20s. That means at that point, the output of the heat pump matches the heat loss of the space so you have NO reserve for a warmup without electric help. Usually better to hit hold on the stat in the 20s.

UPDATE:
It was a multiple of problems that seemed to show up in heating season. First, the Tstat was not wired properly. Second, the ECM Fan Control Board was bad. Third, control wiring at the otdoor HP unit was not correct. The wiring seemed to be all set up for a single compressor, Tstat all the way out to the HP. The control board may have always been bad. My strip heat was never working. The Tstat was indicating it was, but in reality I was just running in single compressor mode. It's all repaired as of tonight. Now all I need is some cold weather to test it out.

UPATE2:
Nights are getting cooler, the unit kicked on at about 4:30am this morning. Fan speed is so low it's hard to detect that it's running. House recovered 3 deg. w/o strip heat...I think. Question: will the blower increase in speed as the second stage compressor kicks in and increase even more if strip heat comes on? Also, do I need to review the Tstat settings to make sure I'm at an optimal set point? I read in another thread how the Tstat can waste money by kicking in the strip heat too soon to make up a small temp recovery faster.

Best not to use setbacks with a heat pump. You're forcing the unit to run more during the coolest part of the day when it's the least efficeint and has the least capacity. Better to only drop the temp 1-2F for comfort, and otherwise leave it at the same temperature. Even after you warm up the air, the interior surfaces will take many more hours to get up to temperature. All of those surfaces radiate heat, making you feel warmer.

Thanks Motoguy128. I've had the White-Rogers 1F94-371 at 2 degrees set back in the night for comfort. I agree that cold soaking is hard on heat pump recovery. (Same with heat soaking the house in summer!) Given the many operational settings this Tstat has (I don't mean the daily temp settings) I want to be sure they are all optimized for my new system. Any tips? (I understand this is not a DIY site, so only looking for some direction here so I can understand how things "should" work!)

Other than the programmable fan and remote sensor option, it's pretty straight forward and doesn;t have much optimizing. Once configured correctly for your type of system, you just set the schedule and let it run. I'ts not like some of hte more advanced stats with adjsutable time delays, humidity control, integrated dual fuel options, anticipator settings and so on.